/*
 * Copyright 2013-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.cloud.sleuth.api.http;

import org.springframework.lang.Nullable;

/**
 * This API is taken from OpenZipkin Brave.
 *
 * Abstract response type used for parsing and sampling. Represents an HTTP response.
 *
 * @author OpenZipkin Brave Authors
 * @author Marcin Grzejszczak
 * @since 3.0.0
 */
public interface HttpResponse extends Response {

	@Nullable
	@Override
	default HttpRequest request() {
		return null;
	}

	/**
	 * @return HTTP method
	 */
	@Nullable
	default String method() {
		HttpRequest request = request();
		return request != null ? request.method() : null;
	}

	/**
	 * Returns an expression such as "/items/:itemId" representing an application
	 * endpoint, conventionally associated with the tag key "http.route". If no route
	 * matched, "" (empty string) is returned. {@code null} indicates this instrumentation
	 * doesn't understand http routes.
	 * @return HTTP route or {@code null} if not set.
	 */
	@Nullable
	default String route() {
		HttpRequest request = request();
		return request != null ? request.route() : null;
	}

	/**
	 * @return The HTTP status code or zero if unreadable.
	 */
	int statusCode();

	/**
	 * @param header header name
	 * @return HTTP header or {@code null} if not set.
	 */
	default String header(String header) {
		return null;
	}

}
